Messaging and social networking applications consistently remain among the top mobile device applications (e.g., applications for tablets and smartphones). As the processing power and sophistication of sensors of these devices grow, there are an increasing number of ways to capture and create content and share it with friends. Typically, text, image and video messages are shared directly between devices or indirectly through social networking sites on the Internet.
We have developed a new approach for messaging through audio signals. This approach communicates a message between devices by passing an audio signal with the message written into the spectrogram of the audio signal. The message is authored, converted to an image format (if not already in suitable image form) and written into the spectrogram of an audio signal.
The resulting audio signal can be communicated in a variety of ways. In one particular embodiment, the audio signal is played from a speaker (e.g., of a sending mobile device) and captured through the microphone of a receiving device. In other embodiment, the audio signal is communicated between sending and receiving devices as a voice telephone call, which is communicated via a telecommunication network in any of the ways such voice calls are transmitted (e.g., cellular voice call, voice over IP, public switched telephone network (PSTN), Plain Old Telephone Service (POTS), asymmetric digital subscriber line (ADSL), integrated services digital network (ISDN), or combinations thereof).
To convert the audio signal into a human readable message, the spectrogram of the received audio signal is computed and then rendered to a display screen (e.g., the display of a receiving mobile device).
A similar approach can be applied to insert these types of message in the spectrogram of other host signal types, such as RF signals other EM signals in the EM spectrum.
An advantage of the proposed scheme is that it is insensitive to time scaling (both Linear and Pitch Invariant Time Scaling), audio compression, ambient detection and clock/carrier synchronization between multiple devices. The message may be read by combining with and also independent of any other signaling protocol.
A messaging system includes a message authoring component, a message writing component, message communication components (transmitter and receiver units), and message rendering components. The implementation of each component can be tailored for certain applications and to add features (e.g., various features to create and customize messages and host signals), as appropriate.
Further features of the invention are described in the following detailed description and accompanying drawings.